The present invention relates to a method of using a medical laser instrument for curing dental and surgical composite materials and for sterilizing living tissue, which provides single line laser light generation from diode pumped solid state microchips.
Cipolla discloses in U.S. Pat. No. 5,616,141 an argon laser dental instrument and method for curing dental composites. However, the laser light consists of multi-line bands of wavelength, of which some wavelength lines must be filtered, since they are not useful for the purpose of curing. Therefore, the system displays an inefficient way of producing the laser line necessary for the curing. In addition, the laser system is an argon gas laser for which a high power cooling system must be supplied in order to operate it. Furthermore, the argon gas laser requires high voltage and a high current power source. Therefore, the instrument can not be made into a compact, hand-held, self-contained unit. A large stationary unit is required to be connected to a separate hand-held portion by optic fibers and cables. Furthermore, the output of the argon laser consists of many lines of wavelength from blue to green of which only the blue line of 488 nm is useful for curing. The beam is collimated and, therefore, has constant power along the propagation length of the beam. This results in uncontrolled curing and air bubble entrapment due to the fact that the surface layers begin to cure prior to the deeper layers.
Vassiliadis et al. in U.S. Pat. No. 4,940,411 discloses a method of eradicating and sterilizing pulp tissue using a pulsed Nd:YAG laser at 1.06.mu.. The unit is not self-contained and cordless, and the wavelength generated can not be used to cure composites. Also, the sterilization is done by obliteration and cauterization and can not be done without killing living tissue. Also disclosed is a dual wavelength laser in U.S. Pat. No. 5,507,739 for dental therapy, but these are 1.06.mu., and 1.32.mu. infrared wavelengths which are not useful for curing composites nor for sterilization of tissue.
Paghdiwala discloses a focused pulsed Er:YAG laser for cutting in dental applications in U.S. Pat. No. 5,401,171. The laser light is generated within a hand-held tool, but the power supply and water cooling pump are external and not self-contained in a hand-held instrument and there is no method disclosed for curing composites nor for tissue sterilization.
Kowalyk et al. discloses a method for removing tooth decay in U.S. Pat. No. 5,456,603 using pulsed, frequency doubled lasers emitting red, green, deep blue, and UV light attenuated by some dye material. Consequently, none of wavelengths described in the patent match the maximum absorption wavelength of medical composites for curing. The device is not a compact, hand-held, self-contained instrument.
Therefore, there remains a need to provide an efficient method for laser curing of dental and surgical composite materials and for laser sterilization of tissue in a cordless, portable, selfcontained, hand-held instrument which generates a single, optimum wavelength for each use.